[antlr-interest] rough idea of exceptions vs no-exceptions backtracking in v3

Terence Parr parrt at cs.usfca.edu
Tue Jan 3 16:21:50 PST 2006


howdy,

I am doing some fuzzy parsing in the lexer using v3.  The basic trick  
of "try to match and if you fail, throw an exception, skip a char and  
retry" works.  It's pretty slow though it turns out.  The exceptions  
per char kill you.  I then tried backtracking using the non-exception  
mechanism in v3 and it's like 5x faster :)

Heh heh heh...thanks to all of you that badgered me into trying to  
build backtracking w/o exceptions. :)

Ter


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